linux-kernel - [PATCH 2/3] media: videobuf2-dma-contig: use dma_mmap

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Message-Id: <1343197764-13659-3-git-send-email-hdk@igel.co.jp>
Date:	Wed, 25 Jul 2012 15:29:23 +0900
From:	Hideki EIRAKU <hdk@...l.co.jp>
To:	Russell King <linux@....linux.org.uk>,
	Pawel Osciak <pawel@...iak.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Mauro Carvalho Chehab <mchehab@...radead.org>,
	Florian Tobias Schandinat <FlorianSchandinat@....de>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org, linux-fbdev@...r.kernel.org,
	Katsuya MATSUBARA <matsu@...l.co.jp>,
	Hideki EIRAKU <hdk@...l.co.jp>
Subject: [PATCH 2/3] media: videobuf2-dma-contig: use dma_mmap_coherent if available

Previously the vb2_dma_contig_mmap() function was using a dma_addr_t as a
physical address.  The two addressses are not necessarily the same.
For example, when using the IOMMU funtion on certain platforms, dma_addr_t
addresses are not directly mappable physical address.
dma_mmap_coherent() maps the address correctly.
It is available on ARM platforms.

Signed-off-by: Hideki EIRAKU <hdk@...l.co.jp>
---
 drivers/media/video/videobuf2-dma-contig.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c
index 4b71326..4dc85ab 100644
--- a/drivers/media/video/videobuf2-dma-contig.c
+++ b/drivers/media/video/videobuf2-dma-contig.c
@@ -101,14 +101,32 @@ static unsigned int vb2_dma_contig_num_users(void *buf_priv)
 static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
 {
 	struct vb2_dc_buf *buf = buf_priv;
+#ifdef ARCH_HAS_DMA_MMAP_COHERENT
+	int ret;
+#endif
 
 	if (!buf) {
 		printk(KERN_ERR "No buffer to map\n");
 		return -EINVAL;
 	}
 
+#ifdef ARCH_HAS_DMA_MMAP_COHERENT
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	ret = dma_mmap_coherent(buf->conf->dev, vma, buf->vaddr, buf->dma_addr,
+				buf->size);
+	if (ret) {
+		pr_err("Remapping memory failed, error: %d\n", ret);
+		return ret;
+	}
+	vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
+	vma->vm_private_data = &buf->handler;
+	vma->vm_ops = &vb2_common_vm_ops;
+	vma->vm_ops->open(vma);
+	return 0;
+#else
 	return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
 				  &vb2_common_vm_ops, &buf->handler);
+#endif
 }
 
 static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
-- 
1.7.0.4

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